1. Field of the Invention
The present invention relates generally to voting systems, and more particularly to an electronic voting system in which a voter verifiable audit log is printed in real-time as actions are taken at a voting terminal.
2. Description of Related Art
In recent years, electronic voting systems have been widely used in elections throughout the world. Typically, an electronic voting system includes multiple voting stations each of which comprises a direct recording electronic (DRE) voting terminal. In operation, a voter selects his/her votes via a touch screen or other input device of the voting terminal. Once the voter casts his/her ballot, the voter's selection of votes are stored in the memory of the voting terminal and electronically tabulated with the vote selections of other voters. Upon poll closing, the vote totals are downloaded from the memory of the voting terminal for final tabulation with the vote totals from other voting terminals.
One issue that has been raised by computer experts with respect to electronic voting systems is that there is no paper record of the voter's selection of votes. As such, many voters are skeptical of the integrity of the election process and believe that their electronic votes may not be counted correctly. In an attempt to resolve this issue, electronic voting systems have been developed in which the voter's selection of votes are printed on either a paper ballot or a paper receipt that may be examined by the voter and/or used for auditing purposes.
In a “paper ballot” type of electronic voting system (an example of which is disclosed in U.S. Pat. No. 6,769,613), each voting station includes a voting terminal with a printer that prints a paper ballot in accordance with the voter's selection of votes. The paper ballot is provided to the voter, whereby the voter has an opportunity to examine the paper ballot for correctness with regard to his/her selection of votes. If the voter observes that the paper ballot correctly represents his/her selection of votes, he/she submits the paper ballot for final tabulation by a tabulating machine. If not, the paper ballot is destroyed and the voter is directed to another voting station to repeat the voting process.
Alternatively, the voter may insert the paper ballot into a ballot scanning machine connected to the voting terminal. If the scanned paper ballot is identical to the selection of votes stored in the memory of the voting terminal, the ballot scanning machine imprints the paper ballot with a validation code and the selection of votes are permanently stored in the memory of the voting terminal. The paper ballot is then returned to the voter who submits the paper ballot for final tabulation by a tabulating machine. If, however, the scanned paper ballot is not identical to the selection of votes stored in the memory of the voting terminal, the ballot scanning machine invalidates the paper ballot and the selection of votes are erased from the memory of the voting terminal. The paper ballot is then destroyed and the voter is directed to another voting station to repeat the voting process.
In a “paper receipt” type of electronic voting system, each voting station includes a voting terminal with an associated printer. After all of the votes have been selected, a summary page listing the voter's selection of votes is displayed on the voting terminal for review by the voter. In addition, the printer prints a paper receipt with a summary of the voter's selection of votes. The paper receipt is not provided to the voter, but is instead retained behind a protective window that allows the voter to examine the paper receipt for correctness with regard to his/her selection of votes. If the voter observes that the paper receipt correctly represents his/her selection of votes, he/she then casts his/her ballot by pressing a “cast ballot” button, whereby the paper receipt may be cut by a paper cutter and dropped into a locked ballot box associated with the voting terminal. If the voter changes his/her mind after reviewing the paper receipt, the voter may reject (i.e., cancel) the ballot and the paper receipt will be marked as “rejected.” The voter may reject the ballot up to two times, just as is regulated with a standard paper ballot.
One problem with the electronic voting systems described above is that they do not track all of the actions taken at the voting terminal. Rather, the paper ballot/paper receipt merely includes a summary of the voter's final selection of votes. As such, auditing the paper ballots would not uncover vote tabulation errors caused by poll worker actions taken at the voting terminal (e.g., in cases where poll workers mistakenly input actual vote selections into the voting terminal because they are not familiar with or trained properly on the voting terminal). In addition, the paper ballot/paper receipt does not include every action taken by the voter during the voting process.
Another problem with some of these electronic voting systems is that the paper receipt must be cut before it is dropped from the voting terminal into a locked ballot box. Thus, the voting terminal must include a paper cutter for cutting the paper receipt, which adds to the complexity and cost of the system. Also, the individual paper receipts are difficult to assemble for recount purposes. In addition, the large amount of storage space required to store the individual paper receipts is similar to that required for mechanical voting systems using standard paper ballots.
Yet another problem with some of these electronic voting systems is that the use of the voting terminal is more complex than “paperless” electronic voting systems. In some systems, the voter must examine the paper ballot and, if acceptable, submit the paper ballot for final tabulation by a tabulating machine. In other systems, the voter must insert the paper ballot into a ballot scanning machine and, if validated, submit the paper ballot for final tabulation by a tabulating machine. In yet other systems, the voter must compare the results of two different methods of display for the ballot (i.e., the paper receipt vs. the summary page displayed on the voting terminal). As a result, the voting terminal must display additional voting instructions and/or instruction screens. Also, the voter's ability to reject a ballot causes the waste of paper. In addition, the voter must perform additional steps and/or spend an increased amount of time in the voting booth (e.g., reviewing the printed summary of vote selections). Furthermore, poll workers must be trained on the use of the voting systems so as to be able to provide adequate voter assistance.